PROJECT SUMMARY/ABSTRACT The goal of this K23 award is to provide Dr. Tae Woo Park, an addiction psychiatrist and Assistant Professor of Psychiatry at Boston University School of Medicine, with the necessary training to establish himself as an independent clinical investigator in the field of reducing the risks of prescription drug misuse. This K23 award focuses on developing and evaluating a distress tolerance (DT)-based treatment for benzodiazepine (BZD) discontinuation in patients receiving opioid agonist therapies (OAT). Assisting Dr. Park will be a local team of multidisciplinary experts in substance use disorder (SUD) research. Dr. Park's primary mentor, Dr. Richard Saitz is an addiction medicine physician and expert in randomized controlled trials (RCTs) involving combined psychosocial and pharmacological interventions for SUD patients. Co-mentors are Dr. Michael Otto, a clinical psychologist and expert in BZD discontinuation and DT-based psychosocial intervention development, Dr. Mari-Lynn Drainoni, an expert in using mixed methods in SUD research, Dr. Howard Cabral, a statistician and expert in RCT data and mediation analyses, and Dr. Jeffrey Samet, an addiction medicine physician-scientist with extensive mentoring experience. Dr. Park's training goals will involve 1) developing expertise in intervention development including qualitative research methods, 2) training in RCT methodology with SUD populations, 3) learning new methods in statistical analyses, and 4) enhancing research career skills including manuscript writing and gaining skills in grantsmanship. BZD use is common in OAT patients and associated with overdose death and reduced OAT treatment retention. Dr. Park's research plan proposes to develop and evaluate a DT-based intervention to assist OAT patients with BZD discontinuation. The plan involves three phases. In Phase 1 (years 1 and 2), we will use qualitative methods to ascertain patients' (n=30) and clinicians' (n=10) intervention preferences with semi- structured qualitative interviews in order to develop a prototype manual for a 12-week Distress Tolerance treatment for BZD Discontinuation (DT-BD) and for a Health Education control condition (HE). In Phase 2 (year 2), we will pilot these interventions in 10 participants receiving OAT who are regularly using BZDs and use data from post-intervention interviews to refine the conditions. In Phase 3 (years 3-5), we will test the DT-BD intervention in a preliminary RCT of 50 additional participants. Participants will be randomized to DT-BD + a BZD taper (n = 25) or the BZD taper + HE (n = 25). Assessments will occur at baseline, weekly during the 12- week treatment, and at 1- and 3-month post-discontinuation follow-ups. The primary outcome will be successful BZD discontinuation determined by self-report confirmed by urine testing. Secondary outcomes are change in BZD use by self-report and change in DT by self-report and behavioral DT measures. We will explore potential mechanisms that may explain the efficacy of the DT intervention. The results of this study will be used to refine the DT-BD intervention so that it can be tested in a larger trial as part of an R01 application.